Thermally stable fullerene derivatives and process for producing the same

ABSTRACT

A fullerene derivative of the formula I ##STR1## where the symbols and indices have the following meanings: F is a fullerene radical of the formula (C 20+2m ), where m is a number from 1 to 50 
     R 1  to R 8  are identical or different and are each H, CO 2  R 9 , CN, COR 10 , Cl, Br, I, F, OR 11 , C 1  -C 20  -alkyl, phenyl or H, R 1  -R 4  and/or R 5 , R 7  can also be part of a cycloalipathic, cycloaromatic or cycloheteroaromatic system which in turn is substituted by C 1  -C 20  -alkyl, aryl, carboxyl, carbonyl, alkoxy, aryloxy, halogen, nitro, alcohol or amine, or R 1  and R 2 , R 2  and R 3 , R 3  and R 4  can together be ##STR2## where R 15  -R 18  are each H, C 1  -C 20  -alkyl, F, Cl, Br, I or phenyl, and 
     AR is the radical of a fused cyclo-aromatic system, and n is from 1 to 20 and a process for its preparation.

RELATED APPLICATIONS

This application claims priority to German Application No. P 43 01458.5, filed Jan. 20, 1993, and to International Application No.PCT/EP93/03658, filed Dec. 22, 1993, both incorporated herein byreference.

Several publications are referenced in this application. Thesereferences describe the state of the art to which this inventionpertains, and are incorporated herein by reference.

BACKGROUND OF THE INVENTION

Fullerenes are cage-like carbon allotropes of the formula (C_(20+2m))(where m=a natural number). They contain twelve five-membered rings andany number, but at least two, six-membered rings of carbon atoms.

Although this class of compounds was not discovered until 1985 by Krotoand Smalley (Nature, 1985, 318, 162) and Kratschmer and Huffmann did notreport the preparation of macroscopic amounts of C₆₀ until 1990 (Nature,1990, 347, 354), such compounds have very quickly attracted wideinterest and within a very short time have become the subject ofnumerous research studies (see, for example, G. S. Hammond, V. J. Kuck(Editors), "Fullerenes", ACS Symposium Series 481, American ChemicalSociety, Washington DC 1992 and Accounts of Chemical Research 1992, 25,98-175).

The use of fullerenes as synthetic building blocks in organic chemistryis beset by great difficulties since, for example, the degree ofsubstitution of fullerenes can be controlled only with difficulty duringthe formation of derivatives. C₆₀ contains 30 double bonds which are inprinciple available as reaction centers. In addition, a very largenumber of positional isomers is possible as soon as even only twosubstituents are present on the fullerene base structure.

Further problems are provided by the low solubility of the fullerenes inall conventional solvents.

However, since there is the expectation of a high potential of thisclass of substances, for example in the fields of optoelectronics andresearch on active compounds, efforts have already been made to formderivatives, in particular of C₆₀ (see, for example, H. Schwarz, Angew.Chemie. 1992, 104, 301 and F. Wudl et al. in "Fullerenes" G. S. Hammond,V. S. Kuck, eds. ACS Symp. Ser. 481, p. 161, Washington DC 1992 andAccounts of Chemical Research, 1992, 25, 157).

It is already known that fullerenes can be reacted with dienes to giveDiels-Alder adducts ("Fullerenes ACS-Symposium Series No. 481, p. 164).The dienophilic reactivity of C₆₀ has hitherto been observed only in thereaction with anthracene and furan and also cyclopentadiene. However,all these reactions have a broad product distribution. Furthermore,these products decompose again on heating into their starting compounds.

It is also known that fullerenes can be reacted with diazo compounds ina 1,3 dipolar cycloaddition (e.g. F. Wudl, Acc. Chem. Res., 1992, 25,157).

It was desirable to synthesize derivatives of fullerenes which arethermally stable, contain the basic fullerene framework, and makepossible further reactions at the derivatized position.

DESCRIPTION OF THE INVENTION

It has now been found that well-defined fullerene derivatives can beobtained by reacting fullerene with a compound of the formula ##STR3##or the formula ##STR4## with the aromatic ring system being bonded tothe fullerene via a cycloaliphatic 6-membered ring.

The invention accordingly provides a fullerene derivative of the formulaI, ##STR5## where the symbols and indices have the following meanings: Fis a fullerene radical of the formula (C_(20+2m)), where m is a numberfrom 1 to 50

R¹ to R⁸ are identical or different and are each H, NH₂, NR⁹ R¹⁰, NR⁹ H,CO₂ R⁹, OCOR¹⁰, CN, COR¹⁰, Cl, Br, I, F, OR¹¹, CONH₂, C₁ -C₂₀ alkylwhich can be substituted by Cl, I, Br and F, C₃ -C₈ -cycloalkyl, aryl,heteroaryl, where R⁹ to R¹¹ are each H, C₁ -C₂₀ -alkyl which can besubstituted by F, Cl, Br or I, pyridinyl or phenyl which in turn can besubstituted by F, Cl, Br, I, nitro, amino, C₁ -C₂₀ -alkylamino, C₆ -C₁₄-arylamino, C₁ -C₂₀ -alkoxy or C₆ -C₁₄ -aryloxy, or --(CH₂)_(j) --CO₂ Hhaving j=1 to 10, R¹ -R⁴ and/or R⁵, R⁷ can also be part of acycloaliphatic, aromatic or heteroaromatic system which is in turnsubstituted by C₁ -C₂₀ -alkyl, aryl, carboxyl, carbonyl, alkoxy,aryloxy, F, Cl, Br, I, nitro, alcohol or amine, or R¹ and R², R² and R³,R³ and R⁴ can in each case together be ##STR6## where R¹⁵ -R¹⁸ are eachH, C₁ -C₂₀ -alkyl, F, Cl, Br, I or phenyl, and AR is the radical of afused aromatic system, R⁵ to R⁸ can also be the structural element ofthe formula V ##STR7## where i is a number from 2 to 20 and k is anumber greater than 1, and R⁵ and R⁷ can together also be an --O--bridge,

n is from 1 to 20.

Preference is given to compounds of the formula I in which the symbolsand indices have the following meanings:

F is a fullerene radical of the formula (C_(20+2m)), where m is 20, 25,28, 29, 31 or 32,

R¹ to R⁸ are as defined above,

n is 1 or 2.

Particular preference is given to compounds of the formula I in whichthe symbols and indices have the following meanings:

F is C₆₀ or C₇₀

R¹ to R⁴ are identical or different and are each H, NH₂, COR⁹, CO₂ R¹⁰,--O--R¹¹, OCOR¹⁰ or C₁ -C₁₀ -alkyl which can be substituted by F, Cl, Bror I, where R⁹ to R¹¹ are each H, (C₁ -C₁₀)-alkyl which can besubstituted by F, Cl or Br, pyridinyl, phenyl which can be substitutedby F, Cl, Br, nitro, amino, C₁ -C₁₀ -alkylamino, C₆ -C₁₄ -arylamino, C₁-C₁₀ -alkoxy or C₆ -C₁₄ -aryloxy,

or --(CH₂)_(j) --CO₂ H having j=1 to 10, or R² and R³ together are##STR8## where R¹⁴ and/or R¹⁵ are each H, phenyl or (C₁ -C₁₀) alkyl, and

R⁵ to R⁸ are identical or different and are each H, F, Cl, Br, (C₁-C₁₂)-alkyl or a structural element of the formula V having i=4 to 12and k being a number greater than 1 and

n is 1 or 2.

Very particular preference is given to compounds of the formula I inwhich the symbols and indices have the following meanings:

F is C₆₀ and

R¹ to R⁴ and also R⁵ to R⁸ have the last-named meanings.

The bonding of the structural element ##STR9## from formula I to thefullerene occurs via two adjacent carbon atoms in the fullerene moleculewhich in turn can be represented as structural element by the formula IIa or II b ##STR10## The compounds of the invention having the formula Iare prepared, for example, by cycloaddition of the compounds III or IVto a fullerene molecule.

This can be carried out in principle by methods known in the literaturefor the addition of a diene to olefins, as described, for example, in I.L. Klundt, Chemical Reviews, 1970, Vol. 70, No. 4, 471-487 and R. P.Thummel, Acc. Chem. Res. 1980, 13, 70-76. Bis(bromomethyl)benzenederivatives (III) can be prepared as described, for example, in I. L.Klundt, Chemical Reviews, 1970, Vol. 70, No. 4, 471-487 and R. P.Thummel, Acc. Chem. Res. 1980, 13, 70-76.1,3-dihydroisothianaphthene-2,2-dioxide derivatives (III, Y=SO₂),benzocyclobutene derivatives IV are prepared as described in A. P. Covc,J. Org. Chem. 1969, 34, 538 or J. A. Chem. Soc. 1959, 81, 4266.

Preference is given to a process for preparing compounds of the formulaI, in which a fullerene of the formula C.sub.(20+2m) (m=0, 1, 2, . . . )is reacted in an aprotic organic solvent such as toluene, CCl₄, CH₂ Cl₂,benzene, chlorobenzene with substituted ortho-alkylbenzenes of theformula III, ##STR11## where R¹ to R⁸ are as defined above and X and Yare each halogen or together are SO₂, CO₂ or N₂, or else compounds ofthe formula IV ##STR12## where R¹ to R⁶ are as defined above.

The reaction can be carried out in a temperature range from 100° to 300°C., preferably from 100° to 210° C. To prepare compounds of the formulaI having n=1, the starting compounds are preferably used instoichiometric amounts.

The fullerene used is very particularly preferably pure C₆₀ and/or C₇₀,but also crude fullerenes which contain a mixture of C₆₀ and C₇₀ as maincomponents. However, it is also possible to use all other conceivablefullerenes or fullerene derivatives.

The fullerenes are, in part, commercially available or can be obtainedby production of fullerene black in an electric arc process usingsubsequent extraction with a nonpolar organic solvent (crudefullerenes), as described in, for example, WO 92/09279. The further fineseparation can be carried out by column chromatography.

EXAMPLES

The compounds of the invention having the formula I can be used inoptoelectronic components.

The invention is illustrated by the following examples. The followingexamples are intended neither to define nor limit the invention in anymanner.

Reaction of Fullerenes with ortho-guinodimethane derivatives

A. Reaction of C₆₀ via base-induced 1,4-elimination of1,2-bis(bromomethyl)aromatics

General procedure:

C₆₀ (100 mg=0.139 mmol), 1,2-bis(bromomethyl) aromatic (0.139 mmol), KI(50 mg=0.3 mmol) and 18!crown-6 (300 mg=1.13 mmol) in 50 ml of tolueneare heated for a number of hours, with the solution changing color. Thecrude product obtained after the usual workup can be purified, forexample, by chromatography.

Example A.1: m=10; n=1, R¹ -R⁸ =H. ##STR13## Reaction time: 6 hours

Yield: 88% (based on C₆₀ reacted)

Characterization:

¹ H-NMR (500 MHz, C₂ Cl₄ D₂, 28° C.): δ=4.46 (d broadened, 2 H; CH₂);4.82 (d broadened, 2 H; CH₂); 7.57-7.59 and 7.69-7.71 (m, AA'BB' systemof the arene); measurement at 125° C.: δ=4.70 (s, 4H; CH₂);

¹³ C-NMR (125 MHz, C₂ Cl₄ D₂, 80° C., J-modulated spin echo for ¹³ C):δ=45.28 (benzyl C); 66.09 (aliphatic quaternary C₆₀ carbon atoms);128.02 and 128.09 (H-substituted aromatic carbon atoms), 135.76, 138.21,140.20, 141.66, 142.13, 142.30, 142.62, 143.17, 144.78, 145.42, 145.49,145.51, 145.85, 146.30, 146.52, 147.76 and 156.93 (17 arene signals).MS(FD): m/e 824 UV/VIS (CHCl₃): Similar to C₆₀, but less structured;weak maximum at 435 nm.

Example A.2: m=20; n=1; R¹ and R⁴ =CH3; R², R³ and R⁵ -R⁸ =H. ##STR14##Reaction time: 8 hours

Yield: 86% (based on C₆₀ reacted)

Characterization:

¹ H-NMR (500 MHz, C₂ Cl₄ D₂, 28° C.), δ=2.58 (s, 6H, CH₃); 4.09(broadened, 4H; CH₂); 7.32 (s, 2H of the arene); ¹³ C-NMR (125 MHz, C₂D₂ Cl₄, 28° C.), δ=29.8 (methyl), 41.2 (CH₂), 66 (aliphatic quaternaryC₆₀ carbon atoms), 128.9 (H-substituted aromatic carbon atoms); 133.2;136.7; 140.2; 141.6; 142.1; 142.3; 142.6; 143.1; 144.8; 145.5; 146.3;146.5; 147.7; 156.8

MS (FD): m/e 852 UV/VIS (CHCl₃): Similar to C₆₀, but less structured;weak maximum at 435 nm.

Example A.3: m=20, n=1, R¹ and R³ -R⁸ =H; R² =OCH3. ##STR15## Reactiontime: 12 hours

Yield: 82% (based on C₆₀ reacted)

Characterization:

¹ H-NMR (500 MHz, C₂ Cl₄ D₂, 28° C.), δ=3.97 (s; OCH₃) 4.41-4.55 (m;broadened; CH₂) 4.76-4.80 (m; broadened; CH₂); 7.08-7.10 (dd; arene H);7.26 (d; arene H); 7.60-7.62 (d, arene H).

MS (FD): m/e 854 UV/VIS (CHCl₃): Similar to C₆₀, but less structured;weak maximum at 435 nm.

B. Reaction of C₆₀ via thermal SO₂ extrusion from compounds of theformula III

Example B.1: m=20; n=1; R¹ -R⁸ =H:

Experimental procedure:

C₆₀ (75 mg=0.104 mmol) and 1,3-dihydroisothianaphthene-2,2-dioxide (25mg=0.149 mmol) in 20 ml of 1,2,4-trichlorobenzene are heated underreflux for 2 days, with the reaction solution becoming brown. Thesolution is admixed with 40 ml of ethanol and the brown precipitatedreaction product is filtered off. The reaction product can be separated,for example by means of chromatography over polystyrene gel crosslinkedwith divinylbenzene (100 Å, 5 μm) using CHCl₃ or toluene as eluants,into unreacted C₆₀, monoaddition product (n=1) and very small amounts ofdiaddition product (n=2). The yield of monoaddition product (n=1) is 81%(based on C₆₀ reacted). For the characterization see Example A.1.

Example B.2: m=20; n=1; R¹ and R⁴ =phenyl; R⁵ -R⁸ =H; R² and R³ =part ofa fused-on benzene ring.

Experimental procedure:

C₆₀ (80 mg=0.111 mmol) and 4,9-diphenyl-1,3-dihydronaphtho2,3-c!thiophene-2,2-dioxide ##STR16## (62 mg=0.167 mmol) in 20 ml of1,2,4-trichlorobenzene are heated under reflux for 3 days, with thereaction solution becoming brown. The reaction mixture is worked up in asimilar manner to Example B.1.

The yield of monoaddition product (n=1) is 75% (based on C₆₀ reacted)

Characterization of the monoaddition product (n=1):

FD mass spectroscopy: 1025.98 (100%, M⁺)

¹ H-NMR (500 MHz, CDCl₃), 4.47 ppm (d, 2H); 4.75 ppm (d, 2H); 7.22-7.7ppm (14H) ¹³ C-NMR (125 MHz, CDCl₃): 42.4 ppm (CH₂); 65.72 ppm(quaternary aliphatic carbon atom of C₆₀) UV (CHCl₃): weak absorptionmaximum at 432.5 nm (characteristic of C₆₀ monoaddition products)

C. Reaction of C₆₀ via thermal ring opening of benzocyclobutenederivatives of the formula IV

Example C.1: m=20; n=1; R¹ -R⁸ =H:

Experimental procedure:

C₆₀ (100 mg=0.139 mmol) and benzocyclobutane ##STR17## (preparationaccording to P. Schiess et al. Tetrahedron Letters 1982, 23, 3665) (16mg=0.154 mmol) in 20 ml of 1,2-dichlorobenzene are heated under refluxfor 3 hours, with the reaction solution becoming brown. The reactionmixture is worked up in a similar manner to Example B.1. The yield ofmonoaddition product (n=1) is 90% (based on C₆₀ reacted). For thecharacterization see Example A.1.

Example C.2: m=20; n=1; R⁵ and R⁷ =Br; R¹ -R⁴, R⁶ and R⁸ =H.

Experimental procedure:

C₆₀ (100 mg=0.139 mmol) and 1,2-dibromobenzocyclobutane ##STR18##(preparation according to M. P. Cava et al. J. Am. Chem. Soc. 1959, 81,6458) (40.5 mg=0.155 mmol) in 20 ml of 1,2-dichlorobenzene are heated at130° C. for 2 hours, with the reaction solution becoming brown. Thereaction mixture is worked up in a similar manner to Example B.1.

The yield of monoaddition product (n=1) is 72% (based on C₆₀ reacted).

Characterization of the monoaddition product (n=1):

FD mass spectroscopy: 981.7 (100%, M⁺); 901.8 (45%, M⁺, Br); 821.9 (87%,M⁺, Br₂)

¹ H-NMR (500 MHz, CDCl₃), 6.96 ppm (s, 1H, CHBr); 7.66 ppm (t, 1H, CH);7.76 ppm (s+t, 2H, CH); 8.04 ppm (s, 1H, CHBr); 8.24 ppm (d, 1H, CH)

¹³ C-NMR (125 MHz, CDCl₃): 56.26 ppm (CHBr); 57.07 ppm (CHBr); 127.13ppm (aromatic CH); 129.22 ppm (aromatic CH); 130.45 ppm (aromatic CH);131.01 ppm (aromatic CH); 155.14, 152.61, 152.53, 151.74, 147.87,147.77, 147.75, 147.54, 146.75, 146.60, 146.57, 146.56, 146.36, 146.26,146.15, 146.08, 145.84, 145.83, 145.59, 145.54, 145.50, 145.43. 145.35,145.30, 144.78, 144.63, 144.37, 144.02, 144.00, 143.97, 143.12, 142.84,142.78, 142.70, 142.68, 142.59, 142.52, 142.37, 142.31, 142.12, 141.69,141.51, 141.50, 141.42, 141.41, 141.38, 141.32, 139.97, 138.53, 138.12,136.64, 136.17, 136.16, 136.02, 135.37 ppm (55 quaternary non-aliphaticcarbon atoms). UV (CHCl₃): weak absorption maximum at 432.5 nm

Example C.3: m=20; n=1; R¹, R³, R⁴, R⁵ and R⁶ =H; R²=4-fluoro-3-nitrobenzoyl. ##STR19##

Experimental procedure:

1055 mg of C₆₀ (1.465 mmol) and 336 mg of4-(4-fluoro-3-nitrobenzoyl)benzocyclobutene (1.2398 mmol) in 200 ml of1,2,4-trichlorobenzene were heated under reflux for 7 hours. The solventwas distilled off in vacuo (20 mbar, 130° C.), the distillation residuewas suspended in 200 ml of CHCl₃, filtered from undissolved C₆₀ andworked up by chromatography. This gave 72% of the monoadduct, 19% of thediadduct and 9% of unreacted C₆₀.

Characterization of the monoaddition product (n=1).

MS (FD: m/e 991.1 ( M!+, 100%) ¹ H-NMR (500 MHz, C₂ D₂ Cl₄, 28° C.):d=4.48 (d (b), 2H, CH₂), 4.81 (d (b), 2H, CH₂), 7.45 (t, 1H, 9 and 10Hz, i), 7.8 (d, 1H, 8 Hz, f), 7.89 (d, 1H, 8 Hz, g), 8.04 (s (b), 1H,e), 8.18 (m, 1H, h), 8.53 ppm (dd, 1H, 2 and 7 Hz, k) ¹³ C-NMR (125 MHz,C₂ D₂ Cl₄, 28° C.; J-modulated spin echo for ¹³ C): d=47.97, 48.19(CH₂), 68.51, 68.56 (sp³ C₆₀ carbon atoms), 122.08, 122.25, 128.49,131.23, 131.40, 131.66, 132.23, 132.29, 132.83 (b), 133.06, 140.10,140.18 (all CH), 119.4, 119.65, 126.65, 136.75, 137.5, 137.52, 138.69,141.06, 142.20, 143.20 (b, plurality of superimposed signals), 144.69(b, plurality of superimposed signals), 145.11 (b, plurality ofsuperimposed signals), 145.17, 145.19, 145.64, 146.16 (b, plurality ofsuperimposed signals), 147.42, 147.72, 147.75, 148.52 (b, plurality ofsuperimposed signals), 149.32, 149.53, 149.55, 150.75, 150.77 (allquaternary non-aliphatic carbon atoms), 195.90 ppm (CO) UV/VIS (CHCl₃):weak absorption maximum at about 435 nm.

Example C.4: m=20; n=1, R⁵ =OCOCH₃, R¹ -R⁴ =H, R⁶ -R⁸ =H. ##STR20##

Experimental procedure:

400 mg (2.3710⁻³ mol) ±-benzocyclobuten-7-yl acetate were heated underreflux with 813 mg (1.1310⁻³ mol) of C₆₀ fullerene in 75 ml of1,2,4-trichlorobenzene for 5 hours. The solvent was subsequentlydistilled off and the solid obtained was dissolved in chloroform. Thesolution was filtered through a 0.25 μm teflon membrane filter andpurified by chromatography over polystyrene gel. Yield: 170 mg ofmonoadduct, 648 mg of diadduct and 374 mg of triadduct.

Characterization of the monoaddition product (n=1):

UV/VIS: (n=1) shows an absorption band at 430 nm. FD mass spectroscopy:m/e=882.2 (M⁺ of (n=1), 66%), 1044.3 (M⁺ of (n=2), 100%), 1206.3 (M⁺ of(n=3), 68%, 1369.5 (M⁺ of (n=4), 4%) (n=1) (mixture of two diastereomers(a) and (b)):

¹ H-NMR (500 MHz, C₂ D₂ Cl₄, 28° C.): δ=2.283 (s, 3H, CH₃, a), 2.288 (s,3H, CH₃, a'), 4.33 (d, 1H, CH₂, 14 Hz, b), 4.45 (d, 1H, CH₂, 14 Hz, b'),4.83 (d, 1H, CH₂, 14 Hz, c), 5.31 (d, 1H, CH₂, 14 Hz, c'), 7.21 (s, 1H,CHOR, d), 7.36 (s, 1H, CHOR, d'), 7.49-7.64 (m, 2×4H), CH, e) ¹³ C-NMR(500 MHz, C₂ D₂ Cl₄, 28° C.; J-modulated spin echo for ¹³ C): δ=44.20,44.56 (aliphatic, secondary carbon atoms), 64.31, 66.37, 69.51, 69.79(aliphatic, quaternary C₆₀ atoms, diastereomers), 120.59, 121.58(quaternary aromatic carbon atoms), 128.09, 128.53, 130.00, 131.22,131.27, 132.37 (ternary aromatic carbon atoms), 134.22, 137.59, 137.65(quaternary aromatic carbon atoms), 141.78, 141.87, 142.10, 142.27,142.72, 142.78, 145.53, 145.59, 145.62, 145.77, 145.84, 146.38, 146.57,146.64, 146.71, 152.55, 155.75, 156.97, 161.64 (quaternary C₆₀ atoms, ineach case a plurality of superimposed signals), 170.57, 170.75 (C=O)

Example C.5: m=20; n=1; ##STR21## R⁶ -R⁸ =H. ##STR22##

Experimental procedure:

400 mg (1.210⁻³ mol) of ±-benzocyclobuten-7-ol4-fluoro-3,5-dinitrobenzoate were heated under reflux together with 596mg (8.2810⁻⁴ mol) of C₆₀ fullerene in 75 ml of 1,2,4-trichlorobenzenefor 5 hours. The solvent was subsequently distilled off and the solidobtained was dissolved in chloroform. The solution was filtered througha 0.25 μm teflon membrane filter. The adducts were separated bychromatography over polystyrene gel. In this way, 270 mg of monoadduct,184 mg of diadduct and 95 mg of triadduct were able to be isolated.

Characterization of the monoaddition product (n=1):

UV/VIS: (n=1) shows an absorption band at 430 nm.

FD mass spectroscopy: m/e=1052 (M⁺ of (n=1), 78%), 1384 (M⁺ of (n=2),100%), 1716 (M⁺ of (n=3), 16%)

(n=1) (mixture of two diastereomers (a) and (b)): ¹³ C-NMR (500 MHz,CDCl₃, J-modulated spin echo): δ=44.02, 44.82 (aliphatic, secondarycarbon atoms), 63.84, 66.14, 68.17, 69.22 (aliphatic, quaternary C₆₀atoms, diasteromers), 120.59, 121.58 (quaternary aromatic carbon atoms),128.09, 128.53, 130.00, 131.22, 131.27, 132.37 (ternary aromatic carbonatoms), 134.22, 137.59, 137.65 (quaternary aromatic carbon atoms),141.78, 141.87, 142.10, 142.27, 142.72, 142.78, 145.53, 145.59, 145.62,145.77, 145.84, 146.38, 146.57, 146.64, 146.71, 152.55, 155.75, 156.97(quaternary C₆₀ atoms, in each case a plurality of superimposedsignals), 161.64 (C=O)

(n=1): ¹ H-NMR (500 MHz, CDCl₃, 28° C.): δ=4.58 (d, 1H, CH₂, 14 Hz, a),4.64 (d, 1H, CH₂, 16 Hz, a'), 4.99 (d, 1H, CH₂, 14 Hz, b'), 5.4 (d, 1H,CH₂, 14 Hz, b), 7.55-7.85 (m, 4H, CH, c), 8.01 (s, 1H, CHOR, d), 8.03(s, 1H, CHOR, d'), 9.12 (s, 2H, CH, e), 9.25 (s, 2H, CH, e')

Example C.6: m=20; n=1; ##STR23##

Experimental procedure:

80 mg (3.5510⁻⁴ mol) of ±-benzocyclobuten-7-yl isonicotinate wereheated under reflux together with 500 mg (6.9410⁻⁴ mol) of C₆₀fullerene in 75 ml of 1,2,4-trichlorobenzene for 5 hours. The solventwas subsequently distilled off and the solid obtained was dissolved inchloroform. The solution was filtered through a 0.25 μm teflon membranefilter. The adducts were subsequently separated over polystyrene gel.Yield: 288 mg of monoadduct and 648 mg of diadduct.

Characterization of the monoaddition product (n=1):

UV/VIS: (n=1) shows an absorption band at 430 nm. FD mass spectroscopy:m/e=945.1 (M⁺ of (n=1), 100%), 1170.2 (M⁺ of (n=2), 20%), 1395.3 (M⁺ of(n=3), 2%) (n=1): ¹³ C-NMR (500 MHz, C₂ D₂ Cl₄, 28° C., J-modulated spinecho): δ=44.5 (aliphatic, secondary carbon atoms), 64.23 (aliphatic,quaternary C₆₀ atoms), 123.43, 129.35, 128.34, 130.40, 131.12 (CH,aromatic carbon atoms), 134.78, 137.98, 140.23, 140.40, 140.61, 140.65,141.76, 141.82, 141.92, 142.08, 142.28 (a plurality of superimposedsignals), 142.82 (a plurality of superimposed signals), 142.88, 142.93(a plurality of superimposed signals), 143.34, 143.38, 144.96 (aplurality of superimposed signals), 145.01 (a plurality of superimposedsignals), 145.40 (a plurality of superimposed signals), 145.64, 145.72,145.76, 145.82, 145.89, 145.91, 145.96, 146.81 (a plurality ofsuperimposed signals), 148.05 (a plurality of superimposed signals),151.25, 153.18, 153.76, 157.19, 157.27 (all quaternary C₆₀ atoms),151.10 (aromatic carbon atoms adjacent to the nitrogen in the pyridineradical), 163.5 (C=O) (n=1): ¹ H-NMR (500 MHz, C₂ D₂ Cl₄, 28° C.,mixture of two diastereomers (a) and (b)): δ=4.52 (d, 1H, CH₂, 14 Hz,a), 4.58 (d, 1H, CH₂, 14 Hz, a'), 4.97 (d, 1H, CH₂, 14 Hz, b'), 5.44 (d,1H, CH₂, 14 Hz, b), 7.60-7.67 (m, 4H, CH, c), 7.72 (s, 1H, CHOR, d),7.74 (s, 1H, CHOR, d'), 8.00 (d, 2H, CH, 6 Hz, e'), 8.12 (d, 2H, CH, 6Hz, e), 8.81 (d, 2H, CH, 5 Hz, f), 8.89 (d, 2H, CH, 6 Hz, f)

D. Reaction of C₆₀ via thermal CO₂ extrusion from compounds of theformula III

Example D.1: m=20; n=1; R¹, R⁴ -R⁸ =H; R², R³ =OCH₃ ; X=O; Y=C=O##STR24## 127 mg of 6,7-dimethoxy-3-isochromanone (0.65 mmol) and 360 mgof C₆₀ fullerene (0.5 mmol) were heated for 24 hours under reflux in 80ml of 1,2,4-trichlorobenzene.

The solvent was distilled off and the mixture was worked up bychromatography. This gave 47% of the monoadduct, 22% of the diadduct and30% of unreacted C₆₀.

Characterization of the monoaddition product (n=1)

MS (FD): m/e 887.4 ( M!⁺ of (n=1), 100), 903 ( M+16!⁺, 5)

¹ H-NMR (500 MHz, C₂ D₂ Cl₄, 28° C.): d=4.01 (s, 6H, --OCH₃), 4.37(d(b), 2H, CH₂, 4.74 (d(b), 2H, CH₂), 7.20 (s, 2H) ¹³ C-NMR (125 MHz, C₂D₂ Cl₄, 28° C.; J-modulated spin echo for ¹³ C): d=58.2 (CH₃), 46.62(CH₂), 67.94 (sp³ C₆₀ carbon atoms), 113.57 (CH, aromatic), 132.06,141.83 (b), 143.33, 143.80, 144.02, 144.29, 144.84, 146.45 (b), 147.18,147.29, 147.57, 147.96, 148.20, 149.40, 150.34, 158.36 (b) ppm (allquaternary nonaliphatic carbon atoms) UV/VIS (CHCl₃): weak absorptionmaximum at 435 nm

Example E: m=20; n=1; R¹, R³ -R⁸ =H, R² = ##STR25## 11 mg (1.110⁻²mmol) of the fluoro-nitro derivative from Example C.3 were dissolved in7 ml of dry dimethylacetamide and admixed with 59.1 mg (0.35 mmol) of4-aminobiphenyl. The reaction mixture was heated at 65° C. for one weekand subsequently admixed with 30 ml of water. After some time, afloccular, brown solid precipitated from the mixture, and this wasfiltered off through a 0.25 μm teflon membrane filter. The filterresidue was eluted from the filter using chloroform and was worked up bychromatography. The yield was almost quantitative.

¹ H-NMR (500 MHz, C₂ D₂ Cl₄, 28° C.): δ=4.48 (b, 2H, CH₂, a), 4.82 (b,2H, CH₂, a), 7.3-7.43 (m, 6H, CH, b, c, d, e), 7.57 (d, 2H, CH, 7.3 Hz,f), 7.65 (d, 2H, CH, 8.4 Hz, g), 7.78 Hz, h), 7.89 (dd, 1H, CH, 1.5 Hzand 8.0 Hz, i), 7.98 (dd, 1H, CH, 2 Hz and 8.0 Hz, j), 8.02 (s, 1H, CH,k), 9.85 (d, 1H, CH, 2 Hz, 1)

¹³ C-NMR (J-modulated spin echo for ¹³ C; 500 MHz, C₂ D₂ Cl₄, 28° C.):δ=48.04, 48.18 (CH₂), 68.63, 68.68 (quaternary aliphatic C₆₀ atoms),119.3, 128.42, 128.49, 130.11, 131.4, 131.7, 132.12, 132.23, 132.65,133.62, 139.87 (all CH), 129.75, 134.96, 139.61, 139.99, 141.06, 141.8,142.77, 142.86, 143.24 (b, a plurality of superimposed signals), 144.66(b, a plurality of superimposed signals), 145.11, 145.21, 145.25,145.61, 146.16 (b, a plurality of superimposed signals), 146.27, 147.72,147.77, 148.51, 149.01, 149.29 (b, a plurality of superimposed signals),149.54 (b, a plurality of superimposed signals), 150.73, 150.76 (allquaternary carbon atoms), 196.37 (C=O)

UV/VIS: weak absorption maximum at 430 nm FD mass spectrum: m/e=1139.6(M⁺, 100%), 720 (M⁺ of C₆₀, 5%), 570.2 (M²⁺, 15%)

We claim:
 1. A fullerene derivative of the formula I ##STR26## where thesymbols and indices have the following meanings: F is a fullereneradical of the formula (C_(20+2m)), where m is a number from 1 to 50R¹to R⁸ are identical or different and are each H, NH₂, CO₂ R⁹, CN,OCOR¹⁰, COR¹⁰, Cl, BR, I, F, OR¹¹, CONH₂, C₁ -C₂₀ -alkyl which can besubstituted by Cl, I, Br and F, C³ -C₈ -cycloalkyl, aryl, heteroaryl,where R⁹ to R¹¹ are each H, C₁ -C₂₀ -alkyl which can be substituted byF, Cl, Br or I, pyridinyl or phenyl which in turn can be substituted byF, Cl, Br, I, nitro, amino, C₁ -C₂₀ -alkylamino, C₆ -C₁₄ -arylamino, C₁-C₂₀ -alkylamino, C₆ -C₁₄ -arylamino, C₁ -C₂₀ -alkoxy or C₆ -C₁₄-aryloxy, or --(CH₂)_(j) --CO₂ H having J=1 to 10, R¹ -R⁴ and/or R⁵, R⁷can also be part of a cycloaliphatic, aromatic or heteroaromatic systemwhich is in turn substituted by C₁ -C₂₀ -alkyl, aryl, carboxyl,carbonyl, alkoxy, aryloxy, F, Cl, Br, I, nitro, alcohol or amine, or R¹and R², R² and R³, R³ and R⁴ can in each case together be ##STR27##where R¹⁵ -R¹⁸ are each H, C₁ -C₂₀ -alkyl, F, Cl, Br, I or phenyl, andAR is the radical of a fused aromatic system, and R⁵ and R⁷ can togetheralso be an --O-- bridge, n is from 1 to
 20. 2. A fullerene derivative asclaimed in claim 1, wherein the symbols and indices have the followingmeanings:F is a fullerene derivative of the formula (C_(20+2m)) in whichm is 20, 25, 28, 29, 31 or 32, n is 1 or
 2. 3. A fullerene derivative asclaimed in claim 1, wherein the symbols and indices have the followingmeanings:F is C₆₀ or C₇₀ R¹ to R⁴ are identical or different and areeach H, NH₂, COR⁹, CO₂ R¹⁰, --O--R¹¹, OCOR¹⁰ or C₁ -C₁₀ -alkyl which canbe substituted by F, Cl, Br or I, where R⁹ to R¹¹ are each H, (C₁-C₁₀)-alkyl which can be substituted by F, Cl or Br, pyridinyl, phenylwhich can be substituted by F, Cl, BR, nitro, amino, C₁ -C₁₀-alkylamino, C₆ -C₁₄ -arylamino, C₁ -C₁₀ -alkoxy or C₆ -C₁₄ -aryloxy,or--(CH₂)_(j) --CO₂ H having j=1 to 10, or R² and R³ together are##STR28## where R¹⁴ and/or R¹⁵ are each H, phenyl or (C₁ -C₁₀)-alkyl,and R⁵ to R⁸ are identical or different and are each H, F, Cl, Br, or(C₁ -C₁₂)-alkyl and n is 1 or
 2. 4. A fullerene derivative as claimed inclaim 3, wherein F is C₆₀.